[1][2] The carina is a cartilaginous ridge separating the left and right main bronchi that is formed by the inferior-ward and posterior-ward prolongation of the inferior-most tracheal cartilage.

[3][4] This is in line with the sternal angle, but the carina may raise or descend up to two vertebrae higher or lower with breathing.

[6] The mucous membrane of the carina is the most sensitive area of the trachea and larynx for triggering a cough reflex.

[7] Widening and distortion of the carina is a serious radiological sign that usually indicates carcinoma of the lymph nodes around the region where the trachea divides.

[citation needed] This article incorporates public domain material from Dictionary of Cancer Terms.